2. Specific Question
• How is the demand for electricity
currently being generated?
• In the future?
3. • Almost 80% of electricity is produced
burning fossil fuels such as coal, oil,
and natural gas.
• In future we hope that renewable
energy sources can lead the
production of electricity in each part
of the world.
6. Present Energy
Resources
• Fossil fuels - coal, oil, gas are all of limited
amounts. Can’t be replaced.
• Nuclear fuels -limited amounts of uranium for
nuclear fission reactors.
• Difficult to estimate how long these fuels will
last - but is it sustainable economically or
environmentally?
7. Sustainable situation
• Renewable energy resources are being
replaced / generated at the same rate that
they are being utilised.
• Hence they will last indefinitely.
9. • Renewable energy is the one that is
replaced over a reasonable period of
time by natural processes.
• Forms of renewable energy are wind,
hydroelectricity, geothermal energy,
solar energy and tidal energy.
• Renewable energy can replace non-
renewable energy saving earth from
global warming and air pollution.
11. The List of
Renewable Resources
Wind, Wave and Hydro Power
Photovoltaics Active Solar Heating
Municipal and General Wastes
Landfill Gas Geothermal
Agricultural and Forestry Wastes
Energy Crops Fuel Cells
12. Forms of Renewable
Energy
• All sources of energy ultimately come from the
sun.
• This is particularly obvious in the case of
renewable energies.
14. Solar Radiation
• solar heating panels (for heating)
• solar power generation (for electricity)
• solar cells / photovoltaic cells
15. Solar cells
• convert light into a small electrical output -
milliwatts output.
• need a bank/array of cells for useful output.
• cost of cells is high but reducing.
• efficiency of cells is up to 23%/ improving.
16. Solar Panels
• are situated on roof of building.
• absorb heat in the form of radiation from sun.
• basically system is like a domestic central heating
radiator painted black/insulated.
• provides “topping up” of domestic hot water.
18. Solar Power Generation
• located in desert/high intensity/long sunlight
hours
• parabolic mirrors reflect/focus sun’s rays onto
metal water pipe located along focal axis of
mirrors.
• High temperature produced - steam -
electrical power generated
20. Windpower
• Each windturbine can produce between 1/4
and 2 MW (megawatt) of electrical power.
• Windfarm needs to be located where there is a
relatively high average wind speed.
• Advantages?
• Disadvantages?
24. Offshore Wind
Cluster Features
• Larger average wind speed than
onshore
• Easier planning consent (there
are no barriers)
• Suitable location
25. Hydroelectric
• Currently largest source of electricity from
renewables.
• Needs guaranteed supply of water.
• Kinetic energy of water rotates turbines which
generate electricity.
28. • Water falls from the resevoir into a
penstock.
• Flowing water spins a large turbine
which activates a generator that
produces electricity.
• After passing through the turbine the
water re-enters the river on the
downstream side of the dam.
32. Tidal Power
• Located at some coastal sites - usually
estuaries and bays with large tidal range.
• Shape of coastal site above and below sea
level determines range
• At high tide reservoir of water is created
which is allowed to ebb through turbines
located in dam.
• Expensive construction.
